Slaked Lime Limestone (Ca(OH)₂)

🧪 SLACK LIME (CALCIUM HYDROXIDE): A valuable mineral additive to adjust the pH of growing substrates, especially for gourmet mushrooms like oyster mushrooms.
⚖️ PH REGULATION: Increases and stabilizes the pH of the substrate, preventing the development of undesirable microorganisms and promoting rapid colonization of the mycelium.
🌿 HYGIENIC PREPARATION OF THE SUBSTRATE: Ideal for cold pasteurization techniques (cold water lime pasteurization), ensuring a healthy substrate without cooking.
🔧 EASY TO USE: Easily mixes with straw or other lignocellulosic materials, making substrate preparation quick and efficient.

€5,00

Conditioning

500 gr
5000 gr

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Slaked lime, also called calcium hydroxide, is an additive commonly used in the preparation of substrates for the cultivation of certain mushrooms, particularly species that tolerate or require a substrate with a basic pH (such as some Pleurotus or Stropharia).

Roles of slaked lime in mushroom cultivation

1. Increase in substrate pH

The main function of slaked lime is to increase the pH of the substrate, often quickly and significantly. This allows for:

Create an unfavorable environment for many contaminants (bacteria, molds).
Promote mushrooms tolerant to alkaline pH, such as certain oyster mushrooms.
Replace a heat treatment, in some cases, with a cold chemical pasteurization (notably with straw or cotton hulls), by combining lime and water.

2. Substrate disinfection

At high doses (generally in a limewater soaking preparation), lime acts as a disinfectant agent, significantly reducing the microbial load without requiring thermal sterilization or pasteurization.

3. Improvement of texture and degradation of lignocellulose

Lime can facilitate the degradation of lignocellulose in certain substrates, making plant fibers more accessible to fungal enzymes.

4. Limestone supply

Practical use of slaked lime

Substrate preparation

Cold soaking method (cold lime pasteurization): The straw or a similar substrate is immersed in water containing 1 to 2% slaked lime (10 to 20 g/L of water) for 12 to 24 hours. Then, the substrate is drained and directly inoculated.
It can also be used in small quantities directly in a substrate mixture, but this requires careful control of the doses to avoid inhibiting fungal growth.

Dosage

For cold pasteurization: typically 1–2% of slaked lime per liter of water.
In a mixed substrate: generally less than 1% of the dry weight, with caution.

Precautions for use

Corrosive: slaked lime is caustic; it can cause skin and eye irritation. Wearing gloves and goggles is recommended.
Too high pH: although oyster mushroom mycelium can withstand very high pH levels, an excess can completely inhibit mycelium growth. It is important to adhere to the dosages appropriate for the cultivated mushroom.
Not suitable for all mushrooms: some mushrooms, like shiitakes, prefer a slightly acidic pH and do not tolerate high alkalinity.

Organic farming status

In Europe, slaked lime is permitted in organic farming for certain uses, notably as a substrate treatment agent or disinfectant, according to the rules of Regulation (EU) 2018/848 and its annexes.